Science Project 9 and 10 class. Can you grow a plant upside down? Try it, and see what happens.

Roll a blotter around the inside of a glass. Fasten it with gummed tape. Place several radish seeds near the rim, between the blotter and the glass. Keep the water level in the glass just below the radish seeds for a few days.

After a few days the seeds sprout. Tiny roots start downward and small stems and leaves go upward.

As soon as the leaves of one radish plant get above the top of the glass, pour out the water, turn the glass upside down, and place the rim on two pencils or strips of wood. Keep the blotter moist by adding water several times a day. Do the plants grow upside down? Not at all! The leaves turn and grow upward while the roots grow down-ward again.

The young plant “senses” that it must send its leaves up and the roots down. Why is it so important for the plant to do this?

Why Do Roots Grow Down?

When you are hungry you go to the refrigerator and get some food. When a plant needs food there is only one way to get it—and that’s by making it. In fact the plant has the only real food factory in the entire world. Our factories simply start with food that comes from plants and change it a bit to make it more digestible or tasty. The plant is such a good food factory that scientists have not yet been able to make food the way a plant does. What does a plant need to make its food? You can find out by doing some experiments

Radish seeds are excellent for these experiments. They sprout quickly and grow well. Plant several seeds to be sure that at least one comes up. If you have no flower pots use a paper cup to plant the seeds Make a hole in the bottom of the cup and place it in a dish. It is a good idea to soak the seeds for a day before planting them in earth in the container. This will help the seeds to sprout Plant your radish seeds about a half inch down in the earth. Water the container every day. Grow radish plants for about ). week in two different containers Then stop watering one and keel, watering the other. See what happens. In a week or so, depending upon the size of the containers, the one that gets no water shrivels up and begins to die.

About 3/4 of the body of a plant is water. If water is not supplied, the plant can’t make food and it can’t grow. And, as the water dries out, the body of the plant shrinks and changes. The plant dies. You can see this happen with a celery stalk. Cut off the bottom of the stalk and leave it in the open overnight. In the morning the celery is limp. Put the cut end in water. It soon freshens up and becomes firm once again. The water that has been lost is now replaced.

Why must roots grow downward? When it rains, water soaks into the ground. In order for the plant to get water it must send its roots down into the earth where the water is located. Somehow the root senses “down” and grows in that direction.

Why Do Stems Grow Upward?

Try this experiment. Grow radish plants in two small containers. Give both water. But keep one on a sunny window sill and keep the other in a dark closet. In a few weeks the plant in the dark closet dies. The one that gets light continues to grow.

The plant makes food from two materials, carbon dioxide and water. The carbon dioxide comes from the air. Water comes from the ground. Both are put together inside the leaves of the plants to make sugar, the basic food of all living things.But water and carbon dioxide don’t combine to form sugar by themselves.

Something done to get them to join. Sunlight provides the energy which does this important job. This process is called photosynthesis.Try this experiment. Grow a radish plant in the dark until it is about an inch high. Then place it on the windowsill. In a few hours the leaves lean over toward the window as though seeking more light.

Now we can see why the stem of a plant grows upward. When the seed is below ground the leaves must get up above ground quickly to catch light and make food. The seed has some food for the young plant to get started. But this food is soon used up. If the leaves do not come above ground and start working by the time the food in the seed is used up then the plant will die. So It is a matter of life and death for the plant to push its leaves upward. Wheat. rye, beans, peas, rice, nuts and other seeds make up a large part of our food supply They are nourishing because the parent plant has stored away a supply of ail the important food materials needed by the young plant to get its start in life.

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